<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #contentDiv{
            width: 1200px;
            height: 700px;
            margin:0 auto;
            border: 1px solid #000;
        }
        #navigationDiv{
            margin-left: 10px;
            font-size: 20px;
        }
    </style>
</head>
<body>
    <div id="contentDiv">
        <h1 style="text-align: center">权限管理</h1>
        <div style="display: flex;">
            <div style="width: 200px;height: 300px;" id="navigationDiv">
                <a href="user/user.html" target="contentIframe">用户管理</a><br>
                <a href="role/role.html" target="contentIframe">角色管理</a>
            </div>
            <iframe style="width: 800px;height: 500px" name="contentIframe"></iframe>
        </div>
    </div>

</body>
</html>